[Thermal resistance of Candida tropicalis and Rhodotorula rubra in orange juice]

The thermal resistance of two yeasts (Candida tropicalis and Rhodotorula rubra) was studied. The yeasts were isolated from Venezuelan pasteurized orange juice obtained at retail level. The flask method was utilized, applying temperatures which ranged from 49.5 to 53.5 degrees C to initial populations of 1x10(5) cells/ml of orange juice. Values of D50C=3.4 min and z=4.1 degrees C were found for C. tropicalis, and D50C=2.6 min and z=9.8 degrees C for R. rubra. Linear correlation coefficients of r=0.99 and r=0.98 wee obtained, respectively, for the experimental data.